• DOI:10.1051/0004-6361/200911764
• Corpus ID: 119193286

Infrared photometry and evolution of mass-losing AGB stars. III. Mass loss rates of MS and S stars

@article{Guandalini2010InfraredPA,
  title={Infrared photometry and evolution of mass-losing AGB stars. III. Mass loss rates of MS and S stars},
  author={Roald Guandalini},
  journal={Astronomy and Astrophysics},
  year={2010},
  volume={513}
}

• R. Guandalini
• Published 12 February 2010
• Physics
• Astronomy and Astrophysics

Context. The asymptotic giant branch (AGB) phase marks the end of the evolution for low- and intermediate-mass stars, which are fundamental contributors to the mass return to the inter stellar medium and to the chemical evolution of galaxies. The detailed understanding of mass loss processes is hampered by the poor knowledge of the luminosities and distances of AGB stars. Aims. In a series of papers we are trying to establish criteria perm itting a more quantitative determination of luminosities f or the various types of AGB stars, using the infrared (IR) fluxes as a basis. An updated compilation of the mass loss rates is also required, as it is crucial in our studies of the evolutionary propertie s of these stars. In this paper we concentrate our analysis on the study of the mass loss rates for a sample of galactic S stars. Methods. We reanalyze the properties of the stellar winds for a sample of galactic MS, S, SC stars with reliable estimates of the distance on the basis of criteria previously determined. We then compare the resulting mass loss rates with those previously obtained for a sample of C-rich AGB stars. Results. Stellar winds in S stars are on average less effi cient than those of C-rich AGB stars of the same luminosity. Near-to-mid infrared colors appear to be crucial in our analysis. They show a good correlation with mass loss rates in particular for t he Mira stars. We suggest that the relations between the rates of the stellar winds and both the near-to-mid infrared colors and the periods of variability improve the understanding of the late evolutio nary stages of low mass stars and could be the origin of the relation between the rates of the stellar winds and the bolometric magnitudes.